TAHLEQUAH, Okla. (AP)  A Cherokee Nation hospital in Oklahoma is testing more than 180 patients for HIV and hepatitis after allegations that a nurse reused syringes to administer medications.

The nurse violated protocols by using the same vial of medication and syringe to inject multiple intravenous bags at W.W. Hastings Hospital in Tahlequah, according to Cherokee officials. The nurse no longer works for the tribe, the Tulsa World reported .

“We”re a big government, and we have to do our due diligence to make sure things are handled properly,” said Joe Byrd, speaker of the Cherokee Tribal Council. “You can be sure that I”ll have my pulse on the situation.”

Researchers strongly recommend against reusing syringes with IV bags but say the risk of transmitting a disease by doing so is low, according to a 2010 study by the National Center for Biotechnology Information.

The risk of transmitting hepatitis B was less than 53 in 1 million, while the risk of transmitting hepatitis C was less than 4.3 in 1 million, according to the study. The risk of transmitting HIV was about 0.15 in 1 million.

“Patients were never directly in contact with any needle,” said Brian Hail, the hospital”s CEO. “The likelihood of blood-borne pathogens traveling up the lines into an IV bag or IV tubing to cause cross-contamination from using the same syringe is extremely remote.”

Still, hospital officials said patients who were treated at the hospital between January and April should return for blood tests as a precaution.

About 64 patients had been screened as of Monday, and none tested positive. Officials are also still working to notify eight patients who should be tested, Hail said.